1. Field of the Invention
The present invention relates to sailboat standing rigging, and, more particularly, to retractable masts for sailboats.
2. Description of Related Art
Retractable masts for sail boats are desirable, particularly when the mast must be otherwise stepped f or passing under a low bridge, for transport on a trailer, or for storage. Previous retractable masts have complicated mechanical components which are subject to corrosion or breakage, or require hydraulic or fluid seals between nested portions or lengths which require close tolerances and have seals which are subject to wear and eventual leakage.
U.S. Pat. No. 6,000,354, issued Dec. 14, 2000, to Vanlerberghe describes a retractable mast employing mechanical parts and lines and may be deployed only in a fully extended or fully retracted position. The device of the ""354 patent is subject to wear and corrosion and line breakage.
U.S. Pat. No. 4,718,370, issued Jan. 12, 1988, to Portell-Vila describes a mechanically extendable and retractable mast. The device of the ""370 patent is subject to wear and corrosion in a marine environment and the crank mechanism would be an encumbrance on a boat having a head sail.
U.S. Pat. No. 4,525,999, issued Jul. 2, 1985, to Inman describes a pneumatically operated boom or actuator, extended by the pressure of gasses generated internally by a gas generator. The device of the ""999 patent is for a single permanent deployment and thus is not appropriate for a retractable sailboat mast.
U.S. Pat. No. 4,016,823, issued Apr. 12, 1977 to Davis describes a retractable mast having nested portions locked in an extended state by detents and manually operated. The device of the ""823 patent would be practical only for relatively small masts and is limited to discreet lengths of extension.
U.S. Pat. No. 3,658,189, issued Apr. 25, 1972, to Brown et al. describes a hydraulically operated extendable and retractable boom for use in a vehicle mounted lift using independent hydraulic actuators for each boom section. The device of the ""189 patent is complicated and expensive and would be too heavy for use as a mast on a sailboat, as well as subject to corrosion in a marine environment.
U.S. Pat. No. 2,595,307, issued May 6, 1952, to Selberg describes a hydraulically operated retractable boom or ram for use on a vehicle. The device of the ""307 patent requires close tolerances and seals which are subject to corrosion and subsequent leakage in a marine environment.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.
The present invention is a retractable mast for sailboats. The mast, which retracts telescopically, comprises an inner core containing sealed air chambers which are pressurized when the mast is fully extended. The chamber may contain bags for holding the pressurized air. An air compressor, which may be powered by the boat engine, is utilized to supply pressurized air. A pressurized air bottle may, also, provide pressurized air. Valves control the pressure release for extension or retraction. The mast may also be operated hydraulically or by stored or generated pressurized gas.
Accordingly, it is a principal object of the invention to provide a retractable and extendable mast for use on sailboats.
It is another object of the invention to provide a mast as above having multiple sections which nest together in the fully retracted state and telescope upward upon extension.
It is a further object of the invention to provide a mast as above which contains one or more sealed air chambers within the interior of the mast, which is attached to a source of pressurized fluid which, upon entrance to the sealed air chamber, inflates the chamber, thus extending upper portions of the mast upward.
It is yet another object of the invention to provide a mast as above which contains one or more bags within the interior of the mast, which are attached to a source of pressurized fluid which, upon entrance to the bag, inflates the bag, thus extending upper portions of the mast upward.
Still another object of the invention is to provide a mast which has seals between nested movable mast sections so as to provide an open mast interior which is raised or lowered through control of pneumatic or hydraulic pressure.
Yet another object of the invention to provide a mast as above wherein each movable mast section has a lower end plate having orifices therethrough so as to control the rate of deployment of the nested mast section.
Still another object of the invention is to provide a mast as above which has valves to release the pressurized fluid, allowing the bags to deflate and the upper portions of the mast to retract into the lower portion.
It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.
These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.